 We used a Holley 0-80573S...  We used a Holley 0-80573S 750-cfm mechanical secondary carburetor specifically designed for pull-through supercharger applications. |  The heads used on this test...  The heads used on this test were stock-port Vortecs from Scoggin-Dickey, modified for more valve lift. |  We also used a set of Crane...  We also used a set of Crane Gold Race narrow-body rocker arms to clear the stock valve covers. These rockers are rail-type rockers, which use guides that straddle the valve tip. |
Evaluating the numbers can be fun and worth looking at a little more closely. The addition of the blower increased average torque from a respectable 380 lb-ft to an average of 93 more lb-ft to 473. Also note how close the average torque value is compared with the peak. That means in a car, this combination would be mucho fun to drive with plenty of power at any rpm.
It's also interesting to look at the far-right column-the percentage of power increase. Note how the supercharger tends to do its best job of adding power on either side of peak torque. A normally aspirated engine is most efficient at peak torque, which means the blower can add a greater percentage of power on either side of peak torque.
Quarter-mile Simulation
Just for fun, we plugged this power curve into the Quarter Pro computer dragstrip simulation software from Racing Systems Analysis using a 3,700-pound Chevelle, a TH400 trans with a 2,600-rpm converter, 3.55 rear gears, and a 26-inch-tall by 10.5-inch-wide tire. At 1,000 feet of altitude on a 70-degree day, the simulation reported that the car would run around 11.80s at 115 mph.
Because the engine makes so much torque, we pulled gear out of it all the way down to a set of 3.08s, where it still simulated around 12.00 seconds at 114 mph. Not bad for a full-dress, 3,700-pound street car.